DE2147776C3 - Wide angle (fisheye) lens - Google Patents

Description

F i g. 2A, 2B and 2C are graphs of spherical aberration, astigmatism and the Distortion for the in FIG. 1 lens shown,

F i g. 3 a longitudinal section through the objective according to the invention according to claim 2,

F i g. Figures 4A, 4B and 4C are graphs similar to Figure 4. 2, but based on FIG. 3,

F i g. 5 shows a longitudinal section through the according to the invention Objective according to claim 3.

F i g. 6A, 6B and 6C are graphs similar to FIG. 2, but on F i g. 5 related.

According to the drawing, particularly Figs. 1, 3 or 5, the fisheye lens of the present invention has a front lens group. contains the three scattering lenses Ll, L2 and L3, which are arranged with their convex surfaces towards the object, a biconcave lens L4 and a converging lens LS.

The converging lens LS can be chained together with the biconcave lens LA , as in FIG. 1 and 3 shown. or it can be arranged separately from it, with an air gap remaining, as in FIG. 5 shown. The surface of the lens LS, which is arranged next to the lens L4, is convex. These lenses are arranged in the listed order from the object side and satisfy the following relationships:

these surfaces. These conditions allow the light rays 10 to be incident at angles that are the same or greater than the 90 '' field of view.

The surface of the lens L3, which is attached after the lens Ll , has a radius of curvature which is larger than the effective diameter of this lens, since rays impinging flatly, which enter the lens L3, already through the preceding lenses L 1 and Ll have been broken. The lens L4 is biconcave. Its surface adjacent to the lens L3 is concave with respect to this lens L3. The light refracted by the lenses LS to L3 is refracted further by the lens L4 to then pass through the lens S and enter a subsequent converging lens group with a small angle of incidence, so as to effectively maintain the flatness of the image field.

If the Abbe numbers for the glasses of the diverging lens L4 and the converging lens LS are respectively represented by V ₄ and K ₅ , then they are in the following

Relationship to each other:

2.0>

² >

ξ ²

> 1.0.

> 1.5

f;

where R is ₁ to R _6, the radii of curvature of the successive surfaces of the lenses Ll to L3, and 0 to 0 ,, the effective diameter, since the lens Ll to ΙΛ are all negative lenses, this relationship is used to Aberrationskorreklur in the magnification surfaces.

The described structure of the front lens group for a fisheye lens provides a field angle of 220. but such a lens group whose focal length is negative. must be followed by a converging lens group since it cannot form an actual image. The design of the positive lens group that follows the front group can be seen from the claims. In the tables in these claims, R represents the radius of curvature of successive surfaces of the lenses. 0 is the effective diameter of the successive lens surfaces, d represents the lens thicknesses or air gaps between lenses, η the indices of refraction of the glasses forming the lenses for the yellow helium-d- Spectral line, and Vd are the Abbe numbers of the lens glasses.

With the present invention are wide angle fisheye lenses that are better in simplicity and effectiveness than systems based on State of the art.

For this purpose 2 sheets of drawings

'■ 409 628/344

Claims (2)

Patent claims: I. Wejtwinke.-fish-eye lens with a -scatter ^ arranged rear lens group of positive B ^^^ '^ uoDe three negative meniscus lenses that in the direction of the incident beam path the front lens group ^{dre ne} ^ " _e _ _{the biconcave} (Ll, LZ, 13) in a convex arrangement to the object, a biconcave lens ( M) and. « ^N « "S ^ g'K ^ J lens arranged positive lens (LS) and that the numerical data of the lens the laudatory id jgj r ^ arranged rear lens group of positive B ^^^ '^ di ative meniscus lenses dß i d Rih d iflld Shl d v Total focal length / «6.3 Focal length of the rear lens group BJ. - 37.65 / Relative opening jF / 2.8 Field of view angle 220 ° the R, = + 143.47 • 0. = 213 ai = 7.0 «1 = 1.5168 t 1.62041 ί 1.64831 Vd = 64.2 33.8 R ₂ = + 52.5 02 = 104.6 d ₂ = 28.0 K ₃ = + 76.4 03 = 100.0 d ₃ = 3.8 H ₂ = 1.5168 1.72825 1.53375 Vd = 64.2 55.4 K ₄ = + 31,521 -04 ' = fc61,0 < d. = 21.8 1.7725 49.5 K ₅ = + 150.00 05 = 56.0 d ₅ = 3.0 «3 = 1.5168 1.51823 Vd = 64.2 K ₆ = + 17.1 06 = 33.0 d ₆ = 16.5 R ₇ = -60.0 dj = 7.0 / I ₄ = 1.51823 Vd = 60.3 59.0 R ₈ = +22.625 d _a = 0.6 1.79631 40.8 R ₉ = + 23.9 J ₉ = 12.6 «5 = Wd = 28.3 Kio = + 78.988 slide = 25.0 R _n = oo you = 1.8 M ₆ = 1.71736 (Filter) 29.5 K ₁₂ = 00 d _l2 ---. 2.8 1.5168 64.2 K ₁₃ = + 278.333 d _i3 = 3.00 M ₇ = Vd = K ₁₄ = -185.420 d _i4 = 0.1 K ₁₅ = +52.03 dis = 7.0 M ₈ = Vd = K ₁₆ = -28.5 d _i6 = 2.0 Tl ₉ = Vd = K ₁₇ = -77.0 dn = 13.0 K ₁ S = +45.0 dis = 8.0 «10 = Vd = Ki ₉ ⁼ -14.4 d _l9 = 0.6 «11 = Vd = K ₂ o = -34.5 d ₂₀ = 0.1 R ₂₁ = -110.0 d ₂₁ = 1.0 «12 = Vd = K ₂₂ = + 35.0 d ₂₂ = 3.5 "I ₃ = Vd = R ₂₃ = -25.763 2. Lens with a front lens group according to claim 1, characterized by the following data: Total focal length / = 2.0 Focal length of the rear lens group Bf = 22.306 Relative opening F / 2 Field of view angle 220 ° = +143.47 0. = Be 215 isp ld II / I ₁ «> 1.51729 Vd = 64.3 - R ₁ , Vd = 31.0 = +52.63 02 = 104.5 d \ = 7.0 R ₂ = +76.4 03 = 101.2 <h = 28.0 / ι, τ-, 1.51707 Vd - 64.1 K ₃ . Vd = 82.0 = +33.0 04- 63.0 = 3.8 R * 'Vd = 31.1 = +125.114 05 = 57.2 d * = 21.2 / I ₃ = 1.51707 Vd = 64.1 K ₅ Vd = .60.4 = +17.1 06 = 33.0 d ₅ = 3.0 re following data: = -40.0 db = 16.5 / I ₄ = 1.69037 Vd = 54.9 K ₇ = +20.0 di = 5.0 / I ₅ = 1.68871 Vd = 31.1 K ₈ = +139.1 d _a = 15.0 K ₉ = +600.0 dg = 240.00 / I ₆ = 1.61995 Vd = 60.4 Loo = -234.7 do = 3.0 Ru = +53.0 you = 0.1 H ₇ = 1.48617 Vd = 82.0 Marg = -53.0 ; H ₈ = 1.60321 Vd = 38.1 = +55.0 you = 7.0 13th d _l3 = 1.2 ..Ji ₉ = 1.61624 - Vd = 31.0 K ₁₄ = -788.91 there -. ⁴ '7 R ₁₅ = +48.789 d _l5 = 48.1 / I ₁₀ = 1.48617 Vd = '82, 0 R ₁₆ = -44.5 d _l6 = 4.7 .H ₁₁ = 1.60294 - Vd = 38.1 , Λ? = +63.1 dn = 0.7 ' ,. H ₁₂ = -1.61624 RiH = +1077.78 'Iw = 4.0 ' Ri9 = +40.0 d _ig = i, o; / I ₁₃ = 1.48617 Κ ₂ ο = -60.0 d ₂ o = 4.7 / I ₁₄ = 1.68871 «21 = +60.0 d _2l = 0.8 H ₁₅ = 1.61995 K ₂₂ = -1466.043 . Lens with a d ₂₂ = 4.0 marked by front Lens group 3 after Claim 1, Total focal length / = 10.2 Focal length of the rear lens group Bf, - 25.09 Relative opening F / 4 Field angle 220 ° R ₁ = +143.47 K ₂ = +52.5 K ₃ = +76.4 K ₄ = +31.521 K ₅ = +125.0 0, = 215 02 = 104.5 0 ₃ = 101.2 04 = 63.0 05 = 56.0 Example III </ i = 7.0 </ ₂ = 28.0 d ₃ = 3.8 c / ₄ = 21.8 d ₅ = 3.0 / I ₁ = 1.5168
/ I ₂ = 1.5168
H ₁ = 1.5168 Vd = 64.2 Vd = 64.2 Vd = 64.2 K ₆ = +17.1 0ή- 33.0 R ₇ = -90.0 K ₈ = +25.5 R ₉ = +27.16 K ₁₀ = +180.0 K ₁ , = +31.0 R _n = -29.0 K ₁₃ = -58.0 K ₁₄ = +65.00 K ₁₅ = -16.0 K ₁₆ = -36.14 K ₁₇ = +40.0 K ₁₈ = -26.0 K ₁₉ = -679.823 The invention relates to a wide angle (fisheye) lens with a negative front lens group and a rear lens group positive refractive power. Fisheye lenses differ from conventional super wide-angle lenses in particular in that its not distortion-free image, which reproduces straight lines as curved lines. The shape of the negative lens group can be roughly divided into two categories. In a Category has the radius of curvature of the first surface of the optical system compared to the effective diameter of this surface is of great value, as it is e.g. B. in the German patent 672 393 is shown. In the other category, the first surface of the optical system is dated From the point of view of the object it is convex, and the radius of curvature of the first surface is smaller than it is more effective Diameter, as it is e.g. B. is shown in German Patent 620 538. The diffusing lens group of the former category helps to reduce the size of the whole optical system, while at the same time the large angle of incidence for flat on the first The rays impinging on the surface mean that the rays are strongly refracted on this surface. When As a result, the cross-sectional area of the light beam after refraction is much larger than before refraction, and that in turn not only results in an insufficient amount of Randlichl, but also aberrations that arise because of the extreme refraction of light. When the first face of the optical System plan, as in the German patent 672 393 cited above, the amount of Marginallylc "! In the half-field angle 90 zero. It is thus readily understood that such lens groups cause significant difficulties when they serve as a fisheye lens whose half-image field angle Exceeds 90 '. 776 ε 6th - 60.3 • l§§4 2 147 = 15.5 ■ lit
ff ft; = 7.0 lh = 1.62041 28.3 Yy dy = 0.7 Vd = 54.6 ds = 12.6
= 10.0 "s = 1.72825 26.1 d ₉
do = 10.0 "ft = 1.51454 Vd = 54 *
35.0 ■ i
Ht you Il Il
oo to
"ο Ό »7 = 1.7847 Vd = dn
d _l3 = 11.3
= f, 6 "s =
M ₉ = 1.51454
1.7495 Vd = 60.8 ■ ft you
d _{5 = 10.0 Vd =
Vd = 29.5 - '? f
m d, 6 = 10.0 "10 = 1.56384 . ■ '' V
^; C.
■■ '$ dn = 1.0 »11 = 1.71736 Vd = dm Vd = In the case of the second-mentioned category, the dimensions of the lens system are larger, but the greater depth of the first surface results in a smaller angle of incidence of the rays incident flatly on this surface and accordingly creates less light refraction in this surface. This in turn makes it possible to keep the cross-sectional areas of the light beam before and after the refraction at a moderate value and at a ratio of about 1: 1. This avoids that the amount of edge light is insufficient, and it is actually greater than the amount of light which enters through the center of the image field. However, the lower refractive power of the first surface makes a larger number of lenses necessary in order to make the light rays parallel to the optical axis. However, it is advantageous that, according to the method of operation discussed above, there is no drop in light in the edge area and a large field angle cr can be achieved. A well-known wide-angle fisheye lens for 6 mm focal length has a relative aperture of 1: 5.6 and an angle of view of 220 ° (Camerart. November 1969, p. 46). The front lens group comprises two negative meniscus lenses. A suggested one and also built Weilwinkel fisheye lens for 2.8 mm focal length, a relative aperture of ί: 6.3 and an angle of view of 220 '(MFM. Moderne Fotolechnik 1971, p. 551, Fig. 14) already has three anterior meniscus lenses without achieving the performance data according to the invention have been. The invention is based on the object, primarily, of the relative opening of wide-angle fish-eye lenses to enlarge. The task is based on the Dalcn specified in the claims solved. In the drawings shows F i g. 1 a longitudinal section through the objective according to the invention according to claim 1,